Aqueous primary dispersions, process of their production and use thereof

ABSTRACT

The invention relates to aqueous, cationically stabilized primary dispersions comprising dispersed polymer particles having a Z-average particle diameter of 5 to 500 nm and which are obtainable by emulsion polymerization of at least one olefinically unsaturated monomer (A). The emulsion polymerization takes place in the presence of one or more emulsifiers (EQ) having the following general formula: R 1 —N − (R 2 )(R 3 )(R 4 )X ⊖ , where R 1  is a moiety with 15 to 40 carbon atoms which contains at least one aromatic group and at least one aliphatic group, and which contains at least one functional group selected from hydroxyl groups, thiol groups, and primary or secondary amino groups, and/or has at least one carbon-carbon multiple bond, R 2 , R 3 , and R 4 , independently of one another, are the same or different aliphatic moieties containing 1 to 14 carbon atoms, and X stands for the acid anion of an organic or inorganic acid. The invention further relates to a method for producing the primary dispersions, and to coating agents which include the primary dispersions, and to the use of the primary dispersions for producing electrodeposition coatings, and also to conductive substrates coated with the coating compositions. The invention further relates to emulsifiers which are used for producing the primary dispersions according to the invention.

The present invention relates to aqueous cationically stabilized primarydispersions which contain polymer particles having an average particlediameter of 5 to 500 nm (so-called polymerized “mini-emulsions”). Thepresent invention further relates to a method for producing the aqueousprimary dispersions by mini-emulsion polymerization. The presentinvention further relates to the use of the aqueous primary dispersionsfor producing coating materials, in particular coating materials forautomotive initial coating and the coating compositions themselves. Theinvention further relates to emulsifiers that are used in the productionof the primary dispersions according to the invention.

Mini-emulsions are dispersions composed of water, an oil phase, and oneor more surface-active substances; the particles present in dispersedform have an average particle diameter of 5 to 500 nm. Mini-emulsionsare considered to be metastable (see Emulsion Polymerization andEmulsion Polymers, P. A. Lovell and Mohamed S. El-Aasser, editors, JohnWiley and Sons, Chichester, N.Y., Weinheim, 1997, pages 700ff; MohamedS. El-Aasser, Advances in Emulsion Polymerization and Latex Technology,30th Annual Short Course, Volume 3, Jun. 7-11, 1999, Emulsion PolymersInstitute, Lehigh University, Bethlehem, Pa., US). The so-calledmini-emulsions are widely used in technology, for example in cleansers,cosmetics, or body care products, as well as in coating compositionssuch as electrodeposition coatings.

The production of aqueous primary dispersions by mini-emulsionpolymerization is known, for example, from International Patentapplications WO 82/00148 and WO 98/02466 or German Patent applicationsDE 196 28 143 A1 and DE 196 28 142 A2. In these known methods, themonomers may be copolymerized in the presence of various low-molecular,oligomeric or polymeric hydrophobic substances or co-stabilizers (see DE196 28 142 A2). In addition, hydrophobic organic auxiliary agents havinglittle solubility in water, for example plasticizers, film forming aidssuch as coalescing agents, or other organic additives, may beincorporated into the monomer droplets of the mini-emulsion (see DE 19628 143 A1). WO 82/00148 describes, for example, the use of emulsifiersfor stabilizing the emulsions disclosed therein.

WO 82/00148 discloses in particular the production of cathodicallydepositable resin emulsions, including mini-emulsions, usingcationically adjustable emulsifiers which accumulate on the surface ofthe particles and impart a positive charge to them, which stabilizes theemulsion at pH values below 10. The emulsifiers may bear reactive groupsvia which the emulsifiers may be incorporated into the polymeric resinsystem during the crosslinking reaction. Explicitly mentioned examplesof emulsifiers are the acetic acid salts of fatty monoamines anddiamines such as primary tallow and oleyl amines or the acetic acidsalts of tallow and oleyl diamines. Tallow and oleyl amines containhydrocarbon chains having at least one carbon-carbon double bond.Polymeric emulsifiers may also be used, such as an epoxy phenol adductthat has been reacted with diethanolamine and cationically adjusted withacetic acid. In some exemplary embodiments in WO 82/00148, Ethoduomeen™T13, which is a tertiary amine containing an unsaturated alkyl moiety,is used as co-emulsifier. According to the manufacturer, AkzoNobel, thismaterial is N′,N′,N-tris-(2-hydroxyethyl)-N-tallowyl-1,3-diaminopropane.According to the teaching of WO 82/00148, the cationically adjustedemulsifiers are the only cationic components of the resin system.

In a study by Grabs and Schmidt-Naake (Macromol. Symp. 2009, 275-276,pp. 133-141), mini-emulsions are produced from 2-aminoethyl methacrylatehydrochloride and styrene, butyl acrylate, and/or butyl methacrylate andpolymerized in situ, resulting in resin particles which bear a positivesurface charge due to the positive charge of the aminoethyl methacrylatemonomer, and are thus stabilized in the dispersion. Saturatedcetyltrimethylammonium bromide, which has a quaternary N atom andtherefore bears a permanent positive charge, may be used as a cationicco-emulsifier in production of the dispersion. In both cases, thepositive charge is compensated for by halide anions.

Although the known aqueous primary dispersions and coating materialsbased on primary dispersions of this type already have numerousadvantageous properties, there is still a need for coating agents whichhave improved shear stability, in particular better pumpability. For thecase that the coating compositions are electrodeposition coatingcompositions, in particular cathodic electrodeposition coatingcompositions, such electrodeposition coating compositions have betterultrafiltration capability and long-term stability. Theelectrodeposition coatings which are producible using primarydispersions of the prior art, as described in WO 82/00148, for example,have shortcomings in this regard. In addition to the functions mentionedabove, it is the aim that coating compositions which are obtainable fromthe primary dispersions have improved film formation, and thus allowimproved corrosion protection in the case of use as an electrodepositioncoating. It would be particularly advantageous if the primarydispersions were suitable for facilitating the deposition of metal ionscontained in the electrodeposition coating bath.

An object of the present invention is to provide aqueous primarydispersions which are usable in aqueous coating compositions and whichimpart improved shear stability, in particular improved pumpability andultrafiltration capability, as well as long-term stability to same, andthe aqueous coating agents produced therefrom having better film-formingproperties than those known thus far, so that they may be more widelyused than has been possible heretofore. In particular, it is the aimthat the primary dispersions are obtainable using customarymini-emulsion techniques. A further object of the present invention isto provide coating compositions which contain the primary dispersionsaccording to the invention and which may be used, for example, in thearea of electrodeposition coating as a coating agent component, in orderto improve the film formation of the electrodeposition coatings andachieve increased corrosion protection of metallic substrates. The aimis to maintain the advantages of the aqueous primary dispersions and thecoating materials produced therefrom which are known thus far.

Furthermore, the object of the present invention is to provide a methodfor producing the primary dispersions according to the invention, whichin a simple manner provides aqueous primary dispersions having animproved property profile, and which are provided with the improvedproperties mentioned above, and which in particular have excellentsuitability in coating compositions, in particular in cathodicallydepositable electrodeposition coatings.

One of the objects of the present invention is achieved by providing anaqueous, cationically stabilized primary dispersion comprising

(1) dispersed polymer particles which

-   -   i. have a Z-average particle diameter of 5 to 500 nm, and    -   ii. are obtainable by emulsion polymerization of at least one        olefinically unsaturated monomer (A), the emulsion        polymerization taking place in the presence of one or more        emulsifiers (EQ) having the following formula:        R¹—N⁻(R²)(R³)(R⁴)X^(⊖),    -    where        -   R¹ is a moiety with 15 to 40 carbon atoms which contains at            least one aromatic group and at least one aliphatic group,            and which contains at least one functional group selected            from hydroxyl groups, thiol groups, and primary or secondary            amino groups, and/or has at least one carbon-carbon multiple            bond,        -   R², R³, and R⁴, independently of one another, are the same            or different aliphatic moieties containing 1 to 14 carbon            atoms, and        -   X^(⊖) stands for the acid anion of an organic or inorganic            acid HX.

The term “primary dispersion” is understood in coating technology tomean polymer dispersions which are produced by emulsion polymerization,having a discrete dispersed phase and a distinct phase boundary betweenthe dispersed phase (polymer) and the dispersion agent (water). Primarydispersions are generally thermodynamically unstable with regard tocoagulation. For this reason they must be electrostatically orsterically stabilized, i.e., brought into a thermodynamically metastablestate (see, for example: B. Müller, U. Poth, Lackformulierung andLackrezeptur [Coating Formulation and Preparation], Vincentz Network,Hannover, 2nd Edition, 2005).

However, in conjunction with the primary dispersion according to theinvention as well as the coating compositions, and in particularelectrodeposition coating compositions, described in greater detailbelow, “aqueous” herein means that the volatile portion, i.e., thevolatile portion of the primary dispersion or of the coating agent upondrying at a temperature of 180° C. for 30 min, is preferably composed ofmore than 50% by weight water, particularly preferably more than 70% byweight water, and very particularly preferably more than 90% by weightwater.

The term “mini-emulsion” herein is understood to mean those primarydispersions whose primary dispersion particles have an intensity-basedZ-average particle diameter of 5 to 500 nm, preferably 25 to 500 nm, andparticularly preferably 50 to 500 nm. The primary dispersions of thepresent invention are thus so-called mini-emulsions. The “Z-averageparticle diameter” may be determined according to the principle ofdynamic light scattering in accordance with ISO 13321 and ISO 22412. Forexample, a Zetasizer Nano S from Malvern may be used. The particle sizedetermination is carried out at 25° C. on a primary dispersion accordingto the invention diluted with deionized water (0.1 to 0.5 mL primarydispersion to 100 mL deionized water). The measurement is conductedautomatically, using a 1 to 2 mL sample volume in a disposable cuvette.The measurement is evaluated using standard software of theabove-mentioned measuring device.

With regard to the prior art, it was surprising and not foreseeable bythose skilled in the art that the objects underlying the presentinvention may be achieved by the primary dispersions according to theinvention and the method, described below, for their production, as wellas the coating compositions produced from the primary dispersions. Inparticular, it was surprising that the emulsifiers (EQ) to be usedaccording to the invention do not interfere with the course of the(co)polymerization and also do not result in coagulation of the primarydispersions according to the invention, but, rather, are responsible inlarge part for the improved properties of the primary dispersions andthe coating compositions produced therefrom. It was particularlysurprising that the method according to the invention provides theprimary dispersions according to the invention in a particularly simplemanner without occurrence of the above-described problems known from theprior art. The method according to the invention, as described ingreater detail below, may be varied to a surprisingly great extent, sothat primary dispersions according to the invention may be produced inbatch operations and used directly as thermally crosslinkable coatingmaterials or for producing such coating materials.

According to the invention, the primary dispersions contain dispersedpolymer particles. The size of the polymer particles results directlyfrom the method according to the invention described below. In thisregard, the Z-average particle diameter is 5 to 500 nm, preferably 25 to500 nm, and particularly preferably 50 to 500 nm. It is veryparticularly preferably 50 to 400 nm, 50 to 350 nm.

The primary dispersions according to the invention preferably have ahigh solids content, for example greater than 20% by weight, preferablygreater than 30% by weight. Solids contents of greater than 40% byweight to 45% by weight may even be achieved. The solids content isdetermined by drying 2.0±0.2 g of the primary dispersion for 30 minutesat 180° C. The remaining residue is weighed and set in a ratio for theweigh-in, from which the solids content results. The primary dispersionsaccording to the invention usually have a low viscosity, even with ahigh solids content, which represents a further particular advantage ofthe primary dispersions according to the invention and the coatingmaterials according to the invention produced therefrom.

Olefinically Unsaturated Monomer (A)

An essential starting compound for producing the primary dispersionsaccording to the invention and for the method according to the inventionis the at least one olefinically unsaturated monomer (A). Within thisdocument and in particular in the discussion below, the term“(meth)acrylic” stands for “methacrylic” as well as “acrylic.”

The following are examples of suitable olefinically unsaturated monomers(A):

a1) (meth)acrylic acid esters which are essentially free of acid groups,such as (meth)acrylic acid alkyl esters or (meth)acrylic acid cycloalkylesters containing up to 20 carbon atoms in the alkyl or cycloalkylmoiety, in particular methyl, ethyl, propyl, n-butyl, sec-butyl,tert-butyl, hexyl, ethylhexyl, stearyl, and lauryl acrylate ormethacrylate; cycloaliphatic (meth)acrylic acid esters, in particularcyclohexyl, isobornyl, dicyclopentadienyl,octahydro-4,7-methano-1H-indene methanol, or tert-butylcyclohexyl(meth)acrylate; (meth)acrylic acid oxaalkyl esters or oxacycloalkylesters such as ethyltriglycol (meth)acrylate and methoxyoligoglycol(meth)acrylate having a number average molecular weight M_(n) ofpreferably approximately 300 to 800 g/mol (determinable by gelpermeation chromatography, using a polystyrene standard), or otherethoxylated and/or propoxylated (meth)acrylic acid derivatives that arefree of hydroxyl groups. Higher-functional (meth)acrylic acid alkyl orcycloalkyl esters such as ethylene glycol, propylene glycol, diethyleneglycol, dipropylene glycol, butylene glycol, 1,5-pentanediol,1,6-hexanediol, octahydro-4,7-methano-1H-indene dimethanol, or 1,2-,1,3-, or 1,4-cyclohexanediol di(meth)acrylates; trimethylolpropane di-or tri(meth)acrylate; or pentaerythrite di-, tri-, ortetra(meth)acrylate may also be contained in small quantities. Withinthe scope of the present invention, small quantities ofhigher-functional monomers are understood to mean such quantities thatdo not result in crosslinking or gelling of the copolymers (A);a2) monomers which bear at least one hydroxyl group, one primary,secondary, tertiary, or quaternary amino group, or one alkoxymethylaminogroup or imino group per molecule and which are essentially free of acidgroups, such as hydroxyalkyl esters of acrylic acid, methacrylic acid,or some other alpha,beta-olefinically unsaturated carboxylic acid, whichare derived from an alkylene glycol that is esterified with the acid, orwhich are obtainable by reacting the alpha,beta-olefinically unsaturatedcarboxylic acid with an alkylene oxide, in particular hydroxyalkylesters of acrylic acid, methacrylic acid, ethacrylic acid, crotonicacid, maleic acid, fumaric acid, or itaconic acid, in which thehydroxyalkyl group contains up to 20 carbon atoms, such as2-hydroxyethyl, 2-hydroxypropyl, 3-hydroxypropyl, 3-hydroxybutyl, and4-hydroxybutyl acrylate, methacrylate, ethacrylate, crotonate,maleinate, fumarate, or itaconate; or hydroxycycloalkyl esters such as1,4-bis(hydroxymethyl)cyclohexane, octahydro-4,7-methano-1H-indenedimethanol, or methylpropanediol monoacrylate, monomethacrylate,monoethacrylate, monocrotonate, monomaleinate, monofumarate, ormonoitaconate; or reaction products of cyclic esters, such asepsilon-caprolactone; or olefinically unsaturated alcohols such as allylalcohol, or polyols such as trimethylolpropane mono- or diallyl ether orpentaerythrite mono-, di-, or triallyl ether (with regard to thesehigher-functional monomers a2), the statements made for thehigher-functional monomers a1) analogously apply);N,N-dimethylaminoethyl acrylate, N,N-diethylaminoethyl methacrylate,allylamine, or N-methyliminoethyl acrylate or N,N-di(methoxymethyl)aminoethyl acrylate and methacrylate, or N,N-di(butoxymethyl)aminopropylacrylate and methacrylate; within the scope of the present invention,the emulsifiers (EQ) that are usable according to the invention are notincluded in the monomers a2), even though some emulsifiers (EQ) meet theformal definition of the monomers a2);a3) monomers which bear at least one acid group per molecule which maybe converted to the corresponding acid anion group, such as acrylicacid, methacrylic acid, ethacrylic acid, crotonic acid, maleic acid,fumaric acid, or itaconic acid; olefinically unsaturated sulfonic orphosphonic acids or the partial esters thereof; or maleic acidmono(meth)acryloyloxyethyl ester, succinic acidmono(meth)acryloyloxyethyl ester, or phthalic acidmono(meth)acryloyloxyethyl ester. Within the scope of the presentinvention, the monomers a3) are not used as the sole monomers (A), butinstead are always used in combination with other monomers (A), and onlyin such low quantities that the monomers a3) do not polymerize outsidethe droplets of the mini-emulsion;a4) vinyl esters of monocarboxylic acids, branched in thealpha-position, containing 5 to 18 carbon atoms in the molecule. Thebranched monocarboxylic acids may be obtained by reacting formic acid orcarbon monoxide and water with olefins in the presence of a liquid,strongly acidic catalyst; the olefins may be cracking products ofparaffinic hydrocarbons, such as mineral oil fractions, and may containbranched as well as straight-chain acyclic and/or cycloaliphaticolefins. The reaction of such olefins with formic acid or with carbonmonoxide and water results in a mixture of carboxylic acids in which thecarboxyl groups are situated predominantly on a quaternary carbon atom.Examples of other olefinic starting materials are propylene trimer,propylene tetramer, and diisobutylene. However, the vinyl esters a4) mayalso be produced in a manner, known per se, from the acids, for exampleby reacting the acid with acetylene. Due to their ready availability,vinyl esters of saturated aliphatic monocarboxylic acids containing 9 to11 carbon atoms and branched at the alpha-carbon atom are particularlypreferred, especially Versatic® acids (see Römpp Lexikon, Lacke andDruckfarben [Paints and Printing Inks], Georg Thieme Verlag, Stuttgart,N.Y., 1998, Versatic® acids, pages 605 and 606);a5) reaction products of acrylic acid and/or methacrylic acid with theglycidyl ester of a monocarboxylic acid branched in the alpha-positionand containing 5 to 18 carbon atoms per molecule, in particular aVersatic® acid, or instead of the reaction product, an equivalentquantity of acrylic and/or methacrylic acid which, during or after thepolymerization reaction, is then reacted with the glycidyl ester of amonocarboxylic acid branched in the alpha-position and containing 5 to18 carbon atoms per molecule, in particular a Versatic® acid;a6) cyclic and/or acyclic olefins such as ethylene, propylene,but-1-ene, pent-1-ene, hex-1-ene, cyclohexene, cyclopentene, norbornene,butadiene, isoprene, cylopentadiene, and/or dicyclopentadiene;a7) (meth)acrylic acid amides such as (meth)acrylic acid amide,N-methyl, N,N-dimethyl, N-ethyl, N,N-diethyl, N-propyl, N,N-dipropyl,N-butyl, N,N-dibutyl, N-cyclohexyl, N,N-cyclohexylmethyl, and/orN-methylol, N,N-dimethylol, N-methoxymethyl, N,N-di(methoxymethyl),N-ethoxymethyl, and/or N,N-di(ethoxyethyl) (meth)acrylic acid amide;a8) monomers containing epoxy groups, such as the glycidyl esters ofacrylic acid, methacrylic acid, ethacrylic acid, crotonic acid, maleicacid, fumaric acid, and/or itaconic acid;a9) vinyl aromatic hydrocarbons such as styrene, 1,1-diphenylethylene,alpha-alkylstyrenes, in particular alpha-methylstyrene, and/or vinyltoluene; vinylbenzoic acid (all isomers), N,N-diethylaminostyrene (allisomers), alpha-methylvinylbenzoic acid (all isomers),N,N-diethylamino-alpha-methylstyrene (all isomers), and/orp-vinylbenzenesulfonic acid;a10) nitriles such as acrylonitrile and/or methacrylonitrile;a11) vinyl compounds, in particular vinyl and/or vinylidene dihalidessuch as vinyl chloride, vinyl fluoride, vinylidene dichloride, orvinylidene difluoride; N-vinyl amides such as vinyl-N-methyl formamide,N-vinylcaprolactam, 1-vinylimidazole, or N-vinylpyrrolidone; vinylethers such as ethyl vinyl ether, n-propyl vinyl ether, isopropyl vinylether, n-butyl vinyl ether, isobutyl vinyl ether, and/or vinylcyclohexyl ether; and/or vinyl esters such as vinyl acetate, vinylpropionate, vinyl butyrate, vinyl pivalate, and/or the vinyl ester of2-methyl-2-ethylheptanoic acid;a12) allyl compounds, in particular allyl ethers and esters such asallyl methyl, ethyl, propyl, or butyl ether, or allyl acetate,propionate, or butyrate;a13) polysiloxane macromonomers having a number average molecular weightM_(n) of 1000 to 40,000 and an average of 0.5 to 2.5 ethylenicallyunsaturated double bonds per molecule, in particular polysiloxanemacromonomers having a number average molecular weight M_(n) of 2000 to20,000, particularly preferably 2500 to 10,000 and in particular 3000 to7000, and an average of 0.5 to 2.5, preferably 0.5 to 1.5, ethylenicallyunsaturated double bonds per molecule, as described in DE 38 07 571 A1on pages 5 to 7, in DE 3706095 A1 in columns 3 to 7, in EP 0358153 B1 onpages 3 to 6, in U.S. Pat. No. 4,754,014 A1 in columns 5 to 9, in DE4421823 A1, or in International Patent application WO 92/22615 on page12, line 18 to page 18, line 10; and/ora14) acryloxysilane-containing vinyl monomers, producible by reactinghydroxyfunctional silanes with epichlorohydrin, followed by reacting thereaction product with (meth)acrylic acid and/or hydroxyalkyl and/orhydroxycycloalkyl esters of (meth)acrylic acid.

Further examples of suitable monomers (A) are found in German Patentapplication DE 196 28 142 A1, page 2, line 50 to page 3, line 7.

Basically, any of the above-mentioned monomers a1) to a14), except formonomer a3), may be polymerized by themselves.

According to the invention, however, it is advantageous to use at leasttwo monomers (A), since in this way the property profile of theresulting copolymers may be varied very widely in a particularlyadvantageous manner, and adapted in a very targeted manner to theparticular intended use of the primary dispersions according to theinvention.

The monomers (A) are preferably selected in such a way that(meth)acrylate copolymers result whose property profile is determinedprimarily by the (meth)acrylates described above. Vinyl aromatichydrocarbons a9), in particular styrene, are then preferably used ascomonomer (A).

The emulsifiers (EQ) of formula R¹N⁻(R²)(R³)(R⁴)X^(⊖) used according tothe invention, where R¹ is an oxygen-containing moiety with 15 to 40carbon atoms which contains at least one aromatic group and at least onealiphatic group, R², R³, and R⁴, independently of one another, are thesame or different aliphatic moieties containing 1 to 14 carbon atoms,and X^(⊖) stands for the acid anion of an organic or inorganic acid, mayalso be incorporated into the polymer as polymerizable monomers in thecopolymerization with the monomers (A) during the production of theprimary dispersion, provided that the aliphatic group in the moiety R¹has at least one alkenically or alkynically unsaturated carbon-carbonmultiple bond.

If, for example, the emulsifier EQ1

described and used in the examples is used, it may be incorporated intothe primary emulsion when R stands for C₁₅H_(31-2n) and n≠0, i.e., n=1,2, or 3. In such a case, the emulsifier (EQ) of general formulaR¹—N⁻(R²)(R³)(R⁴)X^(⊖) has 1, 2, or 3 carbon-carbon double bonds in themoiety R¹ which are available for copolymerization with the monomers(A).

Monomers from the above groups a1), a2), and a9) are preferably selectedas monomers (A). Alkyl esters of (meth)acrylic acid, for example C₁-C₄alkyl esters of (meth)acrylic acid and isobornyl (meth)acrylate, arevery particularly preferably used from group a1). Hydroxyalkyl esters of(meth)acrylic acid, for example hydroxy-C₂-C₄ alkyl esters of(meth)acrylic acid, and/or aminoalkyl esters of (meth)acrylic acid,including in particular N,N-dialkylaminoalkyl esters of (meth)acrylicacid, very particularly preferably N,N-di-C₁-C₄ alkylamino-C₂-C₄ alkylesters of (meth)acrylic acid, are very particularly preferably used fromgroup a2). Aminoalkyl esters of (meth)acrylic acid, including inparticular the N,N-dialkylaminoalkyl esters of (meth)acrylic acid, veryparticularly preferably N,N-di-C₁-C₄ alkylamino-C₂-C₄ alkyl esters of(meth)acrylic acid, are particularly preferably used when the emulsifier(EQ) has no polymerizable carbon-carbon double bonds, i.e., is notcapable of copolymerization with the monomers (A), and/or when theprimary emulsion contains no further cathodically depositable resinssuch as epoxy amine resins. However, the aminoalkyl esters of(meth)acrylic acid mentioned above may also be advantageously used inthe presence of polymerizable emulsifiers (EQ) and/or other cathodicallydepositable resins. Vinyl aromatic hydrocarbons, such as styrene and/or1,1-diphenylethylene in particular, may preferably be used as comonomersa9).

At least one monomer (A) is preferably used which contains reactivefunctional groups (a) that are able to undergo thermally initiatedcrosslinking reactions with groups (a) of the same type or withcomplementary reactive functional groups (b). These groups (a) or (a)and (b) may be present in the (co)polymers which result from themonomers (A), and which then have self-crosslinking properties.Accordingly, the primary dispersions according to the invention inquestion and the coating materials according to the invention producedtherefrom are also self-crosslinking.

However, the complementary reactive functional groups (b) may also bepresent in the crosslinking agents (V) described below, which may beadded to the primary dispersions according to the invention before,during, and/or after production thereof. The primary dispersionsaccording to the invention in question and the coating materialsaccording to the invention produced therefrom are externallycrosslinking in this case.

With regard to the terms “self-crosslinking” and “externallycrosslinking,” additional reference is made to Römpp Lexikon, Lacke andDruckfarben, Georg Thieme Verlag, Stuttgart, N.Y., 1998, key word:“Curing,” pages 274 to 276.

The selection of the particular complementary groups (a) or (a) and (b)depends on the one hand on whether they undergo no undesirable reactionsduring storage of primary dispersions according to the invention, and/oroptionally do not interfere with or inhibit additional curing withactinic radiation, and on the other hand, in which temperature range thecrosslinking is to take place.

Crosslinking temperatures from room temperature to 180° C. arepreferably used in the coating materials according to the invention. Forthis reason, preferably used on the one hand are monomers (A) with thio,hydroxyl, methylol, methylol ether, N-methylol-N-alkoxymethylamino,imino, carbamate, allophanate, and/or carboxy groups, but in particularamino, alkoxymethylamino, or hydroxyl groups which occur in the monomersa2), in particular hydroxyl groups, and on the other hand, crosslinkingagents with anhydride, carboxy, epoxy, blocked isocyanate, urethane,methylol, methylol ether, N-methylol-N-alkoxymethylamino, siloxane,amino, hydroxyl, and/or beta-hydroxyalkylamide groups, but in particularblocked isocyanate, urethane, or methylol ether groups. Methylol,methylol ether, and N-methylol-N-alkoxymethylamino groups are preferablyused for producing self-crosslinking primary dispersions according tothe invention.

When particularly reactive complementary groups (a) or (b) such asisocyanate groups are used, the components containing them, preferablythe crosslinking agents, are not added until just before the primarydispersions according to the invention are used for producing thecoating materials according to the invention in question. These coatingmaterials according to the invention are also referred to as two- ormulticomponent systems by professionals in the field.

When less reactive complementary groups (a) or (b) are used, thecomponents containing them are preferably added to the primarydispersions according to the invention before production or duringproduction, so that from the outset they are contained in the primarydispersions produced therefrom, and thus, also in the coating materialsaccording to the invention. These coating materials according to theinvention are also referred to as one-component systems by professionalsin the field. Electrodeposition coatings, for example, are generallyone-component systems of this type.

The (co)polymer formed from the monomers (A) and optionally theemulsifier (EQ) is not subject to any limitations with respect to themolecular weight distribution. However, the (co)polymerization isadvantageously carried out in such a way that a molecular weightdistribution M_(w)/M_(n) of <12, particularly preferably <10, and inparticular <7, results, as measured by gel permeation chromatographyusing polystyrene as standard.

Emulsifier (EQ)

The emulsifier (EQ) used for producing the primary dispersions accordingto the invention has the following general formula:R¹—N⁻(R²)(R³)(R⁴)X^(⊖),whereR¹ is a moiety with 15 to 40 carbon atoms which contains at least onearomatic group and at least one aliphatic group, and which contains atleast one functional group selected from hydroxyl groups, thiol groups,and primary or secondary amino groups, and/or has at least onecarbon-carbon multiple bond,R², R³, and R⁴, independently of one another, are the same or differentaliphatic moieties containing 1 to 14 carbon atoms, andX^(⊖) stands for the acid anion of an organic or inorganic acid.

A carbon-carbon multiple bond is understood herein to mean acarbon-carbon double bond or a carbon-carbon triple bond. Thecarbon-carbon multiple bond is preferably a carbon-carbon double bond.

The emulsifiers (EQ) are a further subject matter of the presentinvention.

The moiety R¹ preferably contains an aromatic group Gr_(arom) and twoaliphatic groups Gr_(ali1) and Gr_(ali2) bound to Gr_(arom). The moietyR¹ preferably has the structure Gr_(ali1)-Gr_(arom)-Gr_(ali2)-.

The moiety R¹ preferably has at least one carbon-carbon multiple bond,particularly preferably at least one carbon-carbon double bond, in theat least one aliphatic group Gr_(ali1). The presence of carbon-carbonmultiple bonds, in particular carbon-carbon double bonds, has a positiveeffect on the shear stability of the dispersions and coating agentsproduced using the emulsifiers. In particular, undesirable migration ofthe emulsifiers in the dispersions and coating composition may beprevented or reduced. The moiety R¹ particularly preferably has one tothree carbon-carbon double bonds in the at least one aliphatic groupGr_(ali1).

The moiety R¹ very particularly preferably has at least onecarbon-carbon multiple bond, in particular at least one carbon-carbondouble bond, preferably one to three carbon-carbon double bonds, in theat least one aliphatic group Gr_(ali1), and in a second aliphatic groupGr_(ali2) that is different from the aliphatic group Gr_(ali1) mentionedabove, additionally contains at least one functional group selected fromhydroxyl groups, thiol groups, and primary or secondary amino groups.Hydroxy groups, thiol groups, and primary or secondary amino groupsdetermine the reactivity of the emulsifier with crosslinkers that aretypical in coatings, for example blocked or nonblocked polyisocyanates,aminoplast resins such as melamine-formaldehyde resins,tris(alkoxycarbonylamino)triazines which are different from theabove-mentioned crosslinkers, and also resins containing epoxy groups.Primary dispersions that contain such emulsifiers which bear hydroxylgroups, thiol groups, and/or primary or secondary amino groups may thusbe chemically incorporated into the coating agent during the curingprocess of a coating agent that is produced using primary dispersions,as the result of which undesirable migration of the emulsifiers may beprevented or reduced.

The at least one aliphatic group Gr_(ali1) in the moiety R¹, which hasat least one carbon-carbon double bond, may be linear or branched, andis preferably linear. It may also be substituted or unsubstituted, andis preferably unsubstituted. In addition, this aliphatic group maycontain heteroatoms selected from the group comprising O, S, and N, butis preferably free of heteroatoms. This aliphatic group in moiety R¹ istherefore particularly preferably linear, unsubstituted, and free ofheteroatoms, and contains one to three double bonds. The group Gr_(ali1)preferably contains 8 to 30, particularly preferably 10 to 22, and veryparticularly preferably 12 to 18 carbon atoms, for example 15 carbonatoms.

The at least one aliphatic group Gr_(ali2) in the moiety R¹, which bearsat least one functional group selected from hydroxyl groups, thiolgroups, and primary or secondary amino groups, with OH groups beingparticularly preferred, and which is different from Gr_(ali1), may belinear or branched, and is preferably linear. It may also be substitutedor unsubstituted, and is preferably unsubstituted. In addition, thisaliphatic group may contain heteroatoms selected from the groupcomprising O, S, and N, with O being preferred. The aliphatic groupGr_(ali2) is preferably directly bound to the nitrogen atom whichappears in the above general formula of the emulsifier (EQ). The atleast one functional group selected from hydroxyl groups, thiol groups,and primary or secondary amino groups is preferably situated in thebeta-position with respect to the nitrogen atom in the above generalformula of the emulsifier (EQ). Another advantage of such emulsifiers,in which a hydroxyl group, thiol group, or a primary or secondary aminogroup is situated in the beta-position with respect to the nitrogen atomof the emulsifier of general formula (EQ), lies in the possibility offorming chelates with metal ions, which is advantageous when the primarydispersions according to the invention are used in a targeted manner incoating compositions from which metal ions are to be deposited. Metalions which are present chelated in this way provide improved deposition,and may increase the corrosion protection effect of these types ofcoatings. A hydroxyl group is very particularly preferably in thebeta-position with respect to this nitrogen atom. The group Gr_(ali2)preferably contains 2 to 10, particularly preferably 2 to 8, and veryparticularly preferably 2 to 6 carbon atoms, for example 2 or 3 carbonatoms.

The aromatic group Gr_(arom) in the moiety R¹ is preferably a phenyleneor naphthylene group, preferably a phenylene group. The aromatic groupGr_(arom) may be substituted or unsubstituted, and is preferablyunsubstituted. The aromatic group Gr_(arom) may contain heteroatomsselected from the group comprising O, S, and N, but is preferably freeof heteroatoms. The group Gr_(arom) preferably contains 6 to 15,particularly preferably 6 to 12, and very particularly preferably 6 to10 carbon atoms, for example 6 carbon atoms.

A moiety (R¹—) of the following formula is very particularly preferred:Gr_(ali1)-Gr_(arom)-Gr_(ali2)-whereGr_(ali1) is linear, unsubstituted, and free of heteroatoms and has oneto three, preferably one or two, double bonds,Gr_(arom) is a phenylene or naphthylene group, andGr_(ali2) is linear, bears a hydroxyl group, preferably in thebeta-position with respect to the nitrogen atom in the general formulaof the emulsifier (EQ), and as a heteroatom additionally contains O inthe form of an ether group, wherein in the case that Gr_(arom) is aphenylene group, the groups Gr_(ali1) and Gr_(ali2) are bound to thephenylene group in the meta-position with respect to one another.

A particular advantage of the present emulsifiers (EQ) lies in thepermanent positive charge of the nitrogen atom in the general formula ofthe emulsifier according to the invention. When reference is made hereinto “nitrogen atom in the general formula of the emulsifier according tothe invention,” the positively charged nitrogen bound to the moietiesR¹, R², R³, and R⁴ is meant. As a result, due to the permanent positivecharge, the dispersion stability and storage stability of such primarydispersions according to the invention or coating compositions producedtherefrom, which otherwise may typically undergo amine-catalyzedreactions, may be increased.

The moieties R², R³, and R⁴, independently of one another, stand for thesame or different aliphatic moieties containing 1 to 14, preferably 2 to10, particularly preferably 2 to 8, carbon atoms. If R¹ contains nofunctional group selected from hydroxyl groups, thiol groups, andprimary or secondary amino groups, it is particularly advantageous whenat least one of the moieties R², R³, and R⁴ bears such a functionalgroup. At least two of the moieties R¹, R², R³, and R⁴ very particularlypreferably bear a functional group selected from hydroxyl groups, thiolgroups, and primary or secondary amino groups. Of these, hydroxyl groupsare very particularly preferred. The mentioned functional group in themoieties R², R³, or R⁴ is particularly preferably terminal, while it isnon-terminal in the moiety R¹.

The moieties R², R³, and R⁴ may be linear or branched, and arepreferably linear. R², R³, and R⁴ may have carbon-carbon multiple bonds,but are preferably saturated.

In addition to the hydroxyl, thiol, and primary and secondary aminogroups mentioned above, the aliphatic moieties R², R³, and/or R⁴preferably contain at least one, preferably exactly one, additionalfunctional group selected from ether groups, ester groups, and amidegroups. The ether oxygen, the —O— of the —O—C(═O) group, and the amidenitrogen of the amide group are preferably situated in the beta-positionwith respect to the nitrogen atom in the general formula of theemulsifier (EQ).

The anion X^(⊖) is the acid anion of an organic or inorganic acid HX,preferably besides halides. It is particularly preferably the anion of amonocarboxylic acid, such as the monocarboxylic acids used in theneutralization of cathodic electrodeposition coating resins. Suitableanions of monocarboxylic acids are preferably those containing 1 to 10carbon atoms, for example acetates or lactates. X^(⊖) particularlypreferably stands for anions of hydroxycarboxylic acids, in particularlactate.

In one particularly preferred embodiment of the present invention, theemulsifier (EQ) is an emulsifier as given in the following formula:

where R stands for C₁₅H_(31-2n) and X^(⊖) stands for lactate or theanion of some other organic acid, and n may be 0 to 3, i.e., the moietyR may have 0 to 3 carbon-carbon double bonds. This compound isobtainable, for example, by adding N,N-dimethylethanolamine lactate to acardanol glycidyl ether of formula

where R stands for C₁₅H_(31-2n) and n=0 to 3, thereby opening theoxirane ring. Cardanol glycidyl ethers of this type are obtainable, forexample, as Cardolite® NC 513 from Cardolite Europe N.V. (Ghent,Belgium).

Starting with cardanol glycidyl ether, for example a number of preferredemulsifiers according to the invention may be produced by adding anammonium salt of general formula HN⁻(R²)(R³)(R⁴)(X^(⊖)) to the oxiranering. The moieties R², R³, and R⁴ herein have the meanings stated above.

The starting product for producing a cardanol glycidyl ether is thenaturally occurring substance cardanol of formula

where R stands for C₁₅H_(31-2n) and n=0 to 3. As is known from thechemistry of natural products, in particular the chemistry of naturallyoccurring fats and oils and the secondary products thereof, thesesubstances are generally present as a mixture of individual compoundshaving different numbers of carbon-carbon double bonds. The naturalproduct cardanol is such a mixture, in which the individual componentsdiffer by the number of double bonds in the chain R. The most commonindividual components contain 0 to 3 double bonds. Cardanol glycidylether is produced by reacting cardanol with epichlorohydrin, forexample.

For all embodiments of the primary dispersions according to theinvention, not only an emulsifier (EQ), but also a mixture of multipleemulsifiers (EQ) may be used. These preferably include those mixtures inwhich a portion of the emulsifiers in the moiety R¹ have carbon-carbonmultiple bonds, and another portion of the emulsifiers in the moiety R¹have no carbon-carbon multiple bonds. When emulsifier mixtures ofmultiple emulsifiers (EQ) are used, preferably more than 50 mol-%,particularly preferably more than 70 mol-%, of the moieties R¹ havecarbon-carbon multiple bonds, with carbon-carbon double bonds beingparticularly preferred. For the cardanol derivatives mentioned above,this means that in the moiety R═C₁₅H_(31-2n), n=1 to 3 preferably inmore than 50 mol-%, particularly preferably more than 70 mol-%, of themoieties R, and n=0 in the remaining moieties R. However, emulsifiermixtures may also be used which are composed only of emulsifiers (EQ)for which n=1 to 3, or those for which n=0.

The emulsifier (EQ) is preferably used in the primary dispersionaccording to the invention in a quantity of 1 to 10% by weight,particularly preferably in a quantity of 2 to 8% by weight, and veryparticularly preferably in a quantity of 3 to 6% by weight, in each casebased on the weight of one liter of the dispersion.

Crosslinking Agent (V)

Very particularly advantageous primary dispersions and coating materialsaccording to the invention result when the monomers (A) and the at leastone emulsifier (EQ) are (co)polymerized in the presence of at least onehydrophobic, i.e., essentially water-insoluble, crosslinking agent (alsoreferred to herein as crosslinker). The essentially water-insolublecrosslinking agents preferably contain the above-described reactivefunctional groups (a) or (b), which undergo crosslinking reactions withthe complementary reactive functional groups (a) or (b) that are presentin the resulting (co)polymers and/or the emulsifier (EQ). The resultingprimary dispersions according to the invention contain the crosslinkingagents in a particularly good distribution, for which reason thecrosslinking reactions proceed particularly well, so that lesscrosslinking agent may be used than in the corresponding dispersionsthat have been produced according to methods of the prior art. Inaddition, the resulting primary dispersions according to the inventionmay be used directly as coating materials according to the invention.

Examples of particularly well-suited hydrophobic, i.e., essentiallywater-insoluble, crosslinking agents are blocked polyisocyanates,tris(alkoxycarbonylamino)triazines, or completely etherified aminoplastresins, with blocked polyisocyanates being very particularly wellsuited.

Blocked Polyisocyanates

Examples of suitable organic polyisocyanates to be blocked are inparticular the so-called coating polyisocyanates having aliphatically,cycloaliphatically, araliphatically, and/or aromatically boundisocyanate groups. Polyisocyanates having an average of 2 to 5,particularly preferably 2.5 to 5, isocyanate groups per molecule arepreferably used.

Examples of particularly suitable polyisocyanates to be blocked arepolyisocyanates having isocyanurate, biuret, allophanate,iminooxadiazindione, urethane, urea, and/or uretdione groups.

Polyisocyanates having urethane groups are obtained, for example, byreacting a portion of the isocyanate groups with polyols such astrimethylolpropane and glycerin. A triisocyanate essentially resultswhen, for example, trimethylolpropane is reacted with 3 equivalents of adiisocyanate.

Preferably used for producing the polyisocyanates to be blocked arealiphatic or cycloaliphatic diisocyanates, in particular hexamethylenediisocyanate, isophorone diisocyanate,dicyclohexylmethane-2,4′-diisocyanate,dicyclohexylmethane-4,4′-diisocyanate,diphenylmethane-2,4′-diisocyanate, diphenylmethane-4,4′-diisocyanate,toluene-2,4-diisocyanate, and toluene-2,6-diisocyanate, diisocyanatesderived from dimer fatty acids as marketed by Henkel under the tradename DDI 1410 and described in Patents WO 97/49745 and WO 97/49747, inparticular 2-heptyl-3,4-bis(9-isocyanatononyl)-1-pentylcyclohexane; or1,2-, 1,4-, or 1,3-bis(isocyanatomethyl)cyclohexane, 1,2-, 1,4-, or1,3-bis(2-isocyanatoeth-1-yl)cyclohexane,1,3-bis(3-isocyanatoprop-1-yl)cyclohexane, or 1,2-, 1,4-, or1,3-bis(4-isocyanatobut-1-yl)cyclohexane,1,8-diisocyanato-4-isocyanatomethyloctane,1,7-diisocyanato-4-isocyanatomethylheptane, or1-isocyanato-2-(3-isocyanatopropyl)cyclohexane, or mixtures thereof.

The diisocyanates as such may likewise be used for producing blockeddiisocyanates. However, they are preferably used not alone, but in amixture with the polyisocyanates, which have an average of more than twoisocyanate groups.

Very particularly preferred are mixtures of polyisocyanates which haveuretdione and/or isocyanurate groups and/or allophanate groups, andwhich are based on diphenylmethane-2,4′-diisocyanate,diphenylmethane-4,4′-diisocyanate, toluene-2,4-diisocyanate, and/ortoluene-2,6-diisocyanate, as well as the addition products of thepresent diisocyanates with polyols, in particular triols such astrimethylolpropane and glycerin.

Examples of suitable blocking agents for producing the blocked di- orpolyisocyanates are the blocking agents known from U.S. Pat. No.4,444,954, such as the following, for example:

b1) phenols such as phenol, cresol, xylenol, nitrophenol, chlorophenol,ethylphenol, t-butylphenol, hydroxybenzoic acid, esters of this acid, or2,5-di-tert-butyl-4-hydroxytoluene;

b2) lactams such as epsilon-caprolactam, delta-valerolactam,gamma-butyrolactam, or beta-propiolactam;

b3) active methylenic compounds such as diethyl malonate, dimethylmalonate, the ethyl or methyl ester of acetic acid, or acetyl acetone;

b4) alcohols such as methanol, ethanol, n-propanol, isopropanol,n-butanol, isobutanol, t-butanol, n-amyl alcohol, t-amyl alcohol, laurylalcohol, ethylene glycol monomethyl ether, ethylene glycol monoethylether, ethylene glycol monopropyl ether, ethylene glycol monobutylether, butyl diglycol, propylene glycol, diethylene glycol monomethylether, diethylene glycol monoethyl ether, propylene glycol monomethylether, methoxymethanol, glycolic acid, glycolic acid esters, lacticacid, lactic acid esters, methylol urea, methylol melamine, diacetonealcohol, ethylene chlorohydrin, ethylene bromohydrin,1,3-dichloro-2-propanol, or acetocyanohydrin;b5) mercaptans such as butyl mercaptan, hexyl mercaptan, t-butylmercaptan, t-dodecyl mercaptan, 2-mercaptobenzothiazole, thiophenol,methylthiophenol, or ethylthiophenol;b6) acid amides such as acetoanilide, acetoanisidine amide, acrylamide,methacrylamide, acetic acid amide, stearic acid amide, or benzamide;b7) imides such as succinimide, phthalimide, or maleimide;b8) amines such as diphenylamine, phenylnaphthylamine, xylidine,N-phenylxylidine, carbazole, aniline, naphthylamine, butylamine,dibutylamine, or butylphenylamine;b9) imidazoles such as imidazole or 2-ethylimidazole;b10) ureas such as urea, thiourea, ethylene urea, ethylene thiourea, or1,3-diphenyl urea;b11) carbamates such as N-phenylcarbamic acid phenyl ester or2-oxazolidone;b12) imines such as ethylene imine;b13) oximes such as acetone oxime, formaldoxime, acetaldoxime,acetoxime, methyl ethyl ketoxime, diisobutyl ketoxime, diacetylmonoxime, benzophenone oxime, or chlorohexanone oxime;b14) salts of sulfurous acid, such as sodium bisulfite or potassiumbisulfite;b15) hydroxamic acid esters such as benzyl methacrylohydroxamate (BMH)or allyl methacrylohydroxamate; orb16) substituted pyrazoles, in particular dimethylpyrazole or triazoles;andb17) mixtures of the above-mentioned blocking agents.

Etherified Aminoplast Resins

Examples of suitable completely etherified aminoplast resins aremelamine resins, guanamine resins, or urea resins. Also suitable are thecustomary, known aminoplast resins whose methylol and/or methoxymethylgroups are partially defunctionalized by carbamate or allophanategroups. Crosslinking agents of this type are described in U.S. Pat. No.4,710,542 A1 and EP 0 245 700 B1, and in the article by B. Singh et al.,“Carbamylmethylated Melamines, Novel Crosslinkers for the CoatingsIndustry” in Advanced Organic Coatings Science and Technology Series,1991, Volume 13, pages 193 to 207.

Tris(alkoxycarbonylamino)triazines

Suitable tris(alkoxycarbonylamino)triazines are described in U.S. Pat.No. 4,939,213 A1, U.S. Pat. No. 5,084,541 A1, or EP 0624577 A1, forexample. In particular, tris(methoxy)-, tris(butoxy)-, and/ortris(2-ethylhexoxycarbonylamino)triazines may be used.

Of the crosslinking agents described above, the blocked polyisocyanatesoffer special advantages, and therefore are very particularly preferablyused according to the invention.

The ratio of monomers (A) containing complementary reactive functionalgroups (a) or (b) to the crosslinking agents may vary over a very widerange. According to the invention, it is advantageous when the molarratio of complementary reactive functional groups (a) or (b) in (A) tocomplementary reactive functional groups (a) or (b) in the crosslinkingagents is 5:1 to 1:5, preferably 4:1 to 1:4, particularly preferably 3:1to 1:3, and in particular 2:1 to 1:2. Particular advantages result whenthe molar ratio is approximately or exactly 1:1.

Further Components of the Primary Dispersions

The further components of the primary dispersions according to theinvention may be divided, on the one hand, into those which are used forcontrolling and carrying out the method according to the invention forproducing the primary dispersions according to the invention, forexample initiators for the radical emulsion polymerization, or compoundsthat are able to regulate the molecular weight of the polymers, such asmercaptans, in particular dodecyl mercaptan; and on the other hand,those which optimize the property profile of the primary dispersionswith regard to the subsequent area of application.

Initiators of the Radical Emulsion Polymerization

The monomers (A) to be used according to the invention and optionally,polymerizable emulsifiers (EQ), are usually reacted with one another inthe presence of at least one water- and/or oil-soluble radical-forminginitiator to form copolymers. The following are examples of usableinitiators: dialkyl peroxides such as di-tert-butyl peroxide or dicumylperoxide; hydroperoxides such as cumol hydroperoxide or tert-butylhydroperoxide; peresters such as tert-butyl perbenzoate, tert-butylperpivalate, tert-butylper-3,5,5-trimethyl hexanoate, ortert-butylper-2-ethyl hexanoate; peroxydicarbonates such asbis(4-tert-butylcyclohexyl)peroxydicarbonate; potassium, sodium, orammonium peroxodisulfate; azo initiators, for example azodinitriles suchas azobisisobutyronitrile; initiators such as benzopinacol silyl ether;or a combination of a non-oxidizing initiator with hydrogen peroxide.

Further examples of suitable initiators are described in German Patentapplication DE 196 28 142 A1, page 3, line 49 to page 4, line 6.Combinations of these initiators may also be used.

The proportion of the initiator in the reaction mixture is preferably0.1 to 1.5% by weight, particularly preferably 0.2 to 1.0% by weight,and very particularly preferably 0.3 to 0.7% by weight, in each casebased on the overall quantity of the monomers (A) and of the initiator.

Molecular Weight Regulators

Water-insoluble molecular weight regulators may preferably be used asmolecular weight regulators. Mercaptans such as tert-dodecyl mercaptanare particularly suitable.

Further Components which Determine the Property Profile of the PrimaryDispersions

Water-insoluble, low-molecular oligomeric or polymeric substances, forexample, may be used as further components of the primary dispersion.Examples of suitable hydrophobic compounds are oligomeric and/orpolymeric polymerization, polycondensation, and/or polyadditionproducts. In particular, polymers which are coordinated with thesubsequent use of the primary dispersion in a certain type of coatingagent may be used. Thus, for example, epoxy amine adducts as commonlyused in coating agents, in particular electrodeposition coatings, may beincorporated before or during the polymerization.

Method According to the Invention for Producing the Primary DispersionsAccording to the Invention

A further subject matter of the present invention is a method forproducing the primary dispersions according to the invention.

The production of the mini-emulsion within the scope of the methodaccording to the invention has no special methodological features, andis carried out in a high shear field using the customary, known methodsof dispersion or emulsification. Examples of suitable methods aredescribed in Patents DE 196 28 142 A1, page 5, lines 1 to 30, DE 196 28143 A1, page 7, lines 30 to 58, or EP 0 401 565 A1, lines 27 to 51.

Thus, a mixture of one or more monomers (A) with at least one emulsifier(EQ), optionally a molecular weight regulator and optionally at leastone crosslinking agent (V), and optionally further components asdescribed above, for example epoxy amine resins, cosolvents, etc., ispreferably initially prepared. This mixture is optionally at leastpartially neutralized with an acid, preferably an organic carboxylicacid such as formic acid or lactic acid, and vigorously stirred until acoarse emulsion forms.

A preferably homogeneous, not yet polymerized mini-emulsion issubsequently produced using a homogenizer, preferably a high-pressurehomogenizer, with introduction of high shear forces, optionally underpressure.

The polymerization subsequently takes place in a suitable reactor. Thecustomary, known stirred tank reactors, stirred tank reactor cascades,tube reactors, loop reactors, or Taylor reactors, as described, forexample, in Patents DE 1071241 B1 or EP 0498583 A1 or in the article byK. Kataoka in Chemical Engineering Science, Volume 50, Issue 9, 1995,pages 1409 to 1416, are suitable as reactors for the (co)polymerizationprocess. The radical copolymerization is preferably carried out instirred tank reactors or Taylor reactors, the Taylor reactors beingconfigured in such a way that the conditions of Taylor flow are met overthe entire length of the reactor, even when the kinematic viscosity ofthe reaction medium greatly changes, in particular increases, due to thecopolymerization.

According to the invention, the copolymerization is carried out in anaqueous medium. In addition to the emulsifiers, optional crosslinkingagents, and optional hydrophobic compounds and optional protectivecolloids described in detail above, the aqueous medium may containcustomary, known coating additives and/or other dissolved solid, liquid,or gaseous organic and/or inorganic, low- or high-molecular substances,provided that they do not adversely affect or even inhibit the(co)polymerization. Within the scope of the present invention, the term“small quantity” is understood to mean a quantity that does noteliminate the aqueous character of the aqueous medium.

However, the aqueous medium may also be pure water.

The (co)polymerization is advantageously carried out at temperaturesabove room temperature (25° C.), preferably with selection of atemperature range from 25 to 95° C., very particularly preferably 30 to90° C. The (co)polymerization preferably takes place under a protectivegas atmosphere, in particular a nitrogen atmosphere.

When particularly highly volatile monomers (A) are used, the(co)polymerization may also be carried out under pressure, preferably1.5 to 3000 bar, particularly preferably 5 to 1500 bar, and inparticular 10 to 1000 bar. In individual cases, temperatures even higherthan 95° C. may be used.

The polymerization is generally activated and initiated by water-solubleinitiators. Examples of suitable initiators are sodium, potassium, andammonium persulfate or tert-butyl hydroperoxide. tert-Butylhydroperoxide, which may be activated by catalytic quantities ofiron(II) ions, for example, is particularly preferably used. Hydroxideions and tert-butoxide radicals are hereby formed. The iron(III) ionsthat are formed may be reduced to iron(II) ions by means of reducingagents. Sodium formaldehyde sulfoxylate, for example, is a suitablereducing agent. In the event of high residual monomer contents, it maybe necessary to carry out postpolymerization with re-addition of furtherquantities of initiator.

In this regard, it has been found that a particular advantage of themethod according to the invention is that it may also be carried out inbatch operations. In other respects, the procedure described in GermanPatent application DE 19628142 A1, page 4, lines 6 to 36 may also beemployed.

Coating Materials According to the Invention

The primary dispersions according to the invention are used forproducing the coating materials according to the invention, or are useddirectly as such, which is a major advantage of the primary dispersionsaccording to the invention. A further subject matter of the presentinvention is therefore coating compositions that are composed of orcontain the primary emulsions according to the invention.

The coating materials according to the invention are preferablypigmented coating compositions, very particularly preferablycathodically depositable electrodeposition coatings. For these uses, atleast one customary, known coating additive may also be added ineffective quantities to the primary dispersions according to theinvention before, during, and/or after their production. In this regard,before or during production of the primary dispersions according to theinvention, only those coating additives are added which do not interferewith or even totally inhibit the mini-emulsion polymerization. Thoseskilled in the art are able to identify such coating additives on thebasis of their general expertise. The mentioned coating additives arepreferably added after production of the primary dispersions accordingto the invention.

Examples of suitable coating additives are pigments as described inRömpp Lexikon, Lacke and Druckfarben, Georg Thieme Verlag, 1998, underEffect pigments, page 176; key word “Metal oxide-mica pigments” to“Metal pigments,” pages 380 and 381; “Iron blue pigments” to “Iron oxideblack,” pages 180 and 181; “Pigments” to “Pigment volume concentration,”pages 451 to 453; “Thioindigo pigments,” page 563; and “Titanium dioxidepigments,” page 567. These additives are used when the coating materialsaccording to the invention are utilized as electrodeposition coatings,fillers, nonmetallic topcoats, or water-based paints, but in particularas electrodeposition coatings, preferably within the scope of theso-called wet-on-wet process (see, for example, European Patent EP 0 089497 B1) for producing multilayer coatings. By their nature, they areomitted when the coating materials according to the invention are usedas clearcoats, for example within the scope of the wet-on-wet process.

Further examples of suitable additives are organic and inorganicfillers, thermally curable reactive diluents, low-boiling and/orhigh-boiling organic solvents, UV absorbers, light stabilizers, freeradical scavengers, thermolabile radical initiators, crosslinkingcatalysts, deaerating agents, slip additives, polymerization inhibitors,defoamers, emulsifiers, wetting agents, adhesion promoters, levelingagents, film-forming auxiliary agents, rheology-controlling additives,or flame retardants. Further examples of suitable coating additives aredescribed in Lehrbuch Lackadditive [Textbook of Coating Additives] byJohan Bieleman, Wiley-VCH, Weinheim, N.Y., 1998.

If the coating materials according to the invention are also to becurable with actinic radiation (dual cure), they preferably containadditives that are curable with actinic radiation. The actinic radiationmay be electromagnetic radiation such as near infrared (NIR), visiblelight, UV light, or X-ray radiation, or may be corpuscular radiationsuch as electron radiation. Examples of suitable additives that arecurable with actinic radiation are known from German Patent DE 197 09467 C1.

The application of the coating materials according to the invention hasno special methodological features, and may take place using anycustomary application method, such as spraying, knife coating,spreading, pouring, dipping, dripping, or rolling, or byelectrodeposition coating, in particular cathodic electrodepositioncoating.

All surfaces to be coated which are not damaged by curing of thecoatings present on the surfaces, using heat and optionally actinicradiation, are suitable as substrates; these include in particularmetals, plastics, wood, ceramic, stone, textiles, fiber composites,leather, glass, glass fibers, glass wool and rock wool, mineral- andresin-bonded construction materials such as gypsum board and cementslabs or roof tiles, and combinations of these materials. Accordingly,the coating material according to the invention is also suitable forapplications outside automotive painting. It is suited in particular forcoating of furniture and industrial coating, including strip coating,container coating, and impregnation or coating of electrotechnicalcomponents. Within the scope of industrial coatings, it is suited forcoating practically all parts for residential or industrial use, such asradiators, household appliances, small metal parts such as screws andnuts, hubcaps, wheel rims, packaging containers, or electrotechnicalcomponents such as motor windings or transformer windings.

In the case of electrically conductive substrates, the primarydispersions according to the invention or the coating compositionsaccording to the invention that are obtainable therefrom may preferablybe applied by means of electrodeposition coating, particularlypreferably cathodic electrodeposition coating.

A further subject matter of the present invention is therefore anelectrodeposition coating composition (also referred to aselectrodeposition coating for short) which includes the primarydispersions according to the invention. Such an electrodepositioncoating composition is suited in particular for cathodic dip coating(CDC). Thus, a further subject matter of the present invention is theuse of the primary dispersions according to the invention for producingelectrodeposition coating compositions, in particular cathodicallydepositable electrodeposition coating compositions.

The electrodeposition coatings according to the invention preferablyhave a solids content of 5 to 50 mass-%, preferably 5 to 35 mass-%. Inthis regard, solids are understood to mean the portion of anelectrodeposition coating that remains after drying at 180° C. for 30min.

As binder, the electrodeposition coatings according to the inventioncontain at least the dispersed polymer particles contained in theprimary dispersions according to the invention and the emulsifiers (EQ)used according to the invention for producing the primary dispersions,in free form and/or polymerized into the polymer particles. The term“binder” herein is understood to mean the nonvolatile portion of aprimary dispersion or of a coating agent, for example anelectrodeposition coating, minus the optionally contained fillers andpigments, according to EN ISO 4618:2006 (German version).

The dispersed polymer particles contained in the primary dispersionsaccording to the invention preferably contain functional groups whichare already reactive, and which are able to undergo thermal crosslinkingreactions with complementary reactive functional groups that are presentin the above-mentioned crosslinking agents. Examples, mentioned above,of suitable reactive functional groups are hydroxyl groups, thiolgroups, and primary and secondary amino groups, in particular hydroxylgroups.

The polymer particles contained in the primary dispersions according tothe invention particularly preferably contain at least one type ofcationic and/or potentially cationic group, which may be co-polymerized,for example by using monomers a2) or emulsifiers (EQ) havingcarbon-carbon multiple bonds. Potentially cationic groups are, forexample, initially uncharged primary, secondary, or tertiary aminogroups which may converted to ammonium groups by protonation withinorganic or preferably organic acids. Since cathodic electrodepositioncoatings usually have a pH of 4.5 to 6.5, which is typically set byadding acids, the pH of the electrodeposition coatings is generallysufficient for converting potentially cationic groups to cationicgroups, i.e., neutralizing them. Examples of suitable acids for thepotentially cationic groups are inorganic and organic acids such assulfuric acid, phosphoric acid, formic acid, acetic acid, lactic acid,propionic acid, alpha-methylolpropionic acid, dimethylolpropionic acid,gamma-hydroxypropionic acid, glycolic acid, tartaric acid, malic acid,citric acid, sugar acids, salicylic acid, 2,4-dihydroxybenzoic acid, orsulfonic acids, such as amidosulfonic acids and alkanesulfonic acids,for example methanesulfonic acid, in particular formic acid, aceticacid, or lactic acid. The above-mentioned acids, as discussed above, arealso suitable for supplying the anions X^(⊖) of the emulsifiersaccording to the invention. The use of hydrochloric acid is notpreferred, and in one preferred embodiment is precluded.

Further examples of potentially cationic groups that can be converted tocations using neutralizing agents and/or quaternizing agents aresecondary sulfide groups or tertiary phosphine groups. Quaternized aminogroups, such as those occurring in particular in the emulsifiers (EQ),are particularly preferred.

Examples of suitable cationic groups are quaternary ammonium groups,tertiary sulfonium groups, or quaternary phosphonium groups, preferablyquaternary ammonium groups or tertiary sulfonium groups, but inparticular quaternary ammonium groups.

In addition to the dispersed polymer particles of the primarydispersions according to the invention whose use is mandatory, furtherbinders which are typical for electrodeposition coatings may becontained in the electrodeposition coating according to the invention.Further binders for electrodeposition coatings are known from thepublications EP 0 082 291 A1, EP 0 234 395 A1, EP 0 227 975 A1, EP 0 178531 A1, EP 0 333 327, EP 0 310 971 A1, EP 0 456 270 A1, U.S. Pat. No.3,922,253 A, EP 0 261 385 A1, EP 0 245 786 A1, EP 0 414 199 A1, EP 0 476514 A1, EP 0 817 684 A1, EP 0 639 660 A1, EP 0 595 186 A1, DE 41 26 476A1, WO 98/33835, DE 33 00 570 A1, DE 37 38 220 A1, DE 35 18 732 A1, orDE 196 18 379 A1. These are preferably resins containing primary,secondary, tertiary, or quaternary amino or ammonium groups and/ortertiary sulfonium groups, with amine numbers preferably between 20 and250 mg KOH/g and a weight average molecular weight of 300 to 10,000Dalton. Amino(meth)acrylate resins, aminoepoxy resins, aminopolyurethaneresins, polybutadiene resins containing amino groups, or modified epoxyresin-carbon dioxide-amine reaction products are used in particular. Theresins known from WO-A-2004/007443 and also used in the experimentalsection of the present invention are very particularly preferred epoxyamine resins.

All customary, known crosslinking agents that contain suitablecomplementary reactive functional groups are acceptable crosslinkingagents. The crosslinking agents are preferably selected from the groupof crosslinking agents described above.

The electrodeposition coatings according to the invention preferablycontain metal compounds in which the metal is present in the form of acation, very particularly preferably bismuth compounds. Such metalcompounds and in particular bismuth compounds are very particularlypreferably contained when the emulsifiers (EQ) contained according tothe invention bear a hydroxyl group, thiol group, or primary orsecondary amino group in the beta-position with respect to the nitrogenatom in the general formula of the emulsifiers (EQ). The above-mentionedgroups that are present in the beta-position facilitate the crosslinkingdensity of the coating.

Furthermore, the electrodeposition coatings according to the inventionmay also contain in effective quantities at least one customary, knownadditive selected from the group of additives described in generalabove.

Pigments are preferably used. The pigments are preferably selected fromthe group comprising customary, known coloring, effect-imparting,electrically conductive, magnetically shielding, fluorescent, filling,and corrosion-inhibiting organic and inorganic pigments.

The electrodeposition coatings according to the invention are producedby mixing the above-mentioned components. The components may behomogenized. The electrodeposition coatings according to the inventionmay optionally be produced with the aid of customary, known mixingprocesses and devices, such as stirred tank reactors, agitator mills,extruders, kneaders, Ultra-Turrax apparatuses, inline dissolvers, staticmixers, micromixers, toothed ring dispersion machines, pressure reliefnozzles, and/or microfluidizers.

The electrodeposition coatings according to the invention are used inparticular for cathodic dip coating. The electrodeposition coatingsaccording to the invention may typically be cathodically deposited onplastic substrates or in particular metallic substrates that areelectrically conductive, for example electrically conductive or madeelectrically conductive by metallization, for example. The inventiontherefore further relates to the method for cathodic deposition of theelectrodeposition coatings according to the invention on substrates ofthis type. In addition, the electrodeposition coatings according to theinvention may be used for producing primer coats by cathodic dip coatingof substrates having electrically conductive surfaces.

Parts made of any common metal, for example the metal parts that arecustomary in the automotive industry, in particular automotive bodiesand their parts, may be used as metallic substrates. Accordingly, theelectrodeposition coatings according to the invention may also be usedin the painting of motor vehicles or their parts.

The curing of the applied coating materials or electrodepositioncoatings according to the invention also has no special methodologicalfeatures, and takes place according to the customary, known thermalprocesses such as heating in a convection oven or irradiation with IRlamps, which in the case of dual cure may also be supplemented byirradiation with actinic radiation. Radiation sources such ashigh-pressure or low-pressure mercury vapor lamps, optionally doped withlead in order to open a radiation window up to 405 nm, or electron beamsources may be used.

The electrically conductive substrates coated with a cathodicelectrodeposition coating layer, which are likewise the subject matterof the present invention, may be coated with one or more additionalcoating layers, for example one or more filler coating layers, one ormore base coating layers, and/or one or more clearcoat layers. Coatedstructures of this type are known in particular from the field ofautomotive painting. In other areas, however, the application of just anelectrodeposition coating layer according to the invention may besufficient.

The invention is explained in greater detail below by use of examples.

EXEMPLARY EMBODIMENTS

Production of Emulsifier EQ1 According to the Invention

Dimethylethanolamine lactate was initially prepared. For this purpose,511.90 parts dimethylethanolamine, 711.9 parts 80% lactic acid, 644.2parts butyl glycol, and 74.8 parts deionized water were stirred for 24hours in a reaction vessel equipped with a stirrer and a reflux cooler.

3057.2 parts Cardolite NC 513 (EEW 532 g/eq) were heated to 60° C., withstirring, in a reaction vessel equipped with a stirrer, reflux cooler,temperature probe, nitrogen inlet, and dropping funnel. 1942.8 parts ofthe above dimethylethanolamine lactate were slowly added dropwise over aperiod of 30 min. The reaction mixture was subsequently stirred until amilliequivalent (MEQ) acid value of 0.116 mmol/g was attained.

Production of a Mini-Emulsion M1 and In Situ Polymerization Thereof:

Production of the Monomer Mixture:

33.7 parts isobornyl methacrylate, 180.8 parts methyl methacrylate,155.9 parts butyl acrylate, 21.6 parts hydroxyethyl methacrylate, 186.2parts styrene, 471.4 parts Araldite GY 2600 (EEW 186 g/eq), 299.0 partsof a crosslinker based on a diphenylmethane diisocyanate oligomer thathad been capped with propylene glycol and butyl diglycol, and present ina 90% 1/1 (w/w) mixture composed of butoxypropanol and phenoxypropanol(CathoGuard® 500 crosslinker, commercial product of BASF Coatings GmbH),3.5 parts tert-dodecyl mercaptan, and 290.0 parts of the emulsifier EQwere stirred until a solution was present. 2104.4 parts deionized waterwere then added slowly, with vigorous stirring. The coarse emulsionwhich formed was subsequently stirred at least for an additional 5minutes.

Production of the Mini-Emulsion:

The coarse emulsion was transferred to an apparatus for introducing highshear forces, and was subsequently homogenized in two passes at 600 barwith a high-pressure homogenizer (Model 110Y from Microfluidics,equipped with one H230Z and one H210Z homogenization chamber).

In Situ Polymerization of the Mini-Emulsion for Producing a PrimaryDispersion According to the Invention:

The mini-emulsion was subsequently heated to 75° C., with stirring, in areaction vessel equipped with a stirrer, reflux cooler, temperatureprobe, nitrogen inlet, and dosing unit. At a temperature of 75° C., 0.8parts of a 1% iron(II) sulfate solution were added, and a solution of4.4 parts sodium formaldehyde sulfoxylate dihydrate in 129.3 partsdeionized water was uniformly added dropwise, concurrently with asolution of 6.1 parts of a 70% tert-butyl hydroperoxide solution in113.1 parts deionized water, over a period of one and one-half hours.Stirring was continued for an additional hour at 75° C., and themini-emulsion polymerized in situ was then cooled to room temperatureand filtered (Nylon filter bag with an 80 μm cutoff).

Particle size (Z-average): 98 nm

Particle distribution index (PDI): 0.10

Solids (after drying for 30 minutes at 180° C.): 32.8% by weight

In all examples, the particle size distribution was determined bydynamic light scattering, using a Zetasizer Nano S from Malvern. The PDIvalue was also derived from this measurement.

Property Testing of the Mini-Emulsion:

Production of a Coating Agent Bath from the Mini-Emulsion M1:

Production of an aqueous preparation for testing the dispersionstability: 1829.3 parts of the mini-emulsion M1 were mixed with 1978.7parts deionized water. 192.0 parts of an aqueous pigment preparation(CathoGuard® 520 pigment paste, commercial product of BASF CoatingsGmbH) were then added, with stirring. The finished bath was stirred forat least 24 additional hours before being tested.

Pump Test:

The pumpability of the bath produced above was tested at 32° C. bypumping in a circuit for 24 hours, using a Little Giant MD 4 magneticdrive centrifugal pump. The sieve residue (25 μm mesh size) wassubsequently determined after burning in at 180° C. for 30 minutes. Thepumpability was assumed to be adequate with a sieve residue <200 mg/L.

A sieve residue of 16 mg/L was determined after the test was completed.

Ultrafiltration Test:

The ultrafiltration of the bath produced above was carried out via aplate module with PVDF membranes having a total surface area of 880 cm²(150 kDa cutoff, commercial product from Microdyn-Nadir GmbH). Forassessing the ultrafiltration capability, the flux performance as wellas the inlet pressure and outlet pressure were determined over a periodof at least one week. The ultrafiltration capability was assumed to beadequate when the flux performance, at a minimum performance of 10L/hm², decreased by less than 20% over the entire test period, with nocontinuous decrease. The following characteristic data for the abovebath were determined during the test:

TABLE Ultrafiltration characteristic data Change Flux compared InletOutlet Duration performance to start pressure pressure Temperature [h][L/hm²] [%] [bar] [bar] [° C.] 0 18.6 0.0 1.1 0.1 26.5 51 21.4 15 1.10.1 28.4 121.5 21.5 15 1.1 0.1 29.4 146 21.3 15 1.2 0.1 29.5 168 21.3 151.2 0.1 28.6

At the end of the test, the flux performance had increased by 15%compared to the start of the test.

The invention claimed is:
 1. An aqueous, cationically stabilized primarydispersion comprising: (1) dispersed polymer particles which i. have aZ-average particle diameter of 5 to 500 nm, and ii. are the reactionproducts of an emulsion polymerization of at least one olefinicallyunsaturated monomer (A), the emulsion polymerization of monomer (A)taking place in the presence of one or more emulsifiers (EQ) having thefollowing formula:R¹—N⁻(R²)(R³)(R⁴)X^(⊖), wherein, R¹ is a moiety with 15 to 40 carbonatoms which contains at least one aromatic group and at least onealiphatic group, and which contains at least one functional groupselected from the group consisting of hydroxyl groups, thiol groups,primary amino groups, secondary amino groups, at least one carbon-carbonmultiple bond, and mixtures thereof, and wherein the R¹ moiety has thestructure Gr_(ali1)-Gr_(arom)-Gr_(ali2)-, where Gr_(arom) stands for anaromatic group, Gr_(ali1) stands for a first aliphatic group, andGr_(ali2) stand for a second aliphatic group, wherein the Gr_(ali1)group has at least one carbon-carbon multiple bond and the Gr_(ali2)group has the at least one functional group selected from hydroxylgroups, thiol groups, and primary or secondary amine groups, R², R³, andR⁴, independently of one another, are the same or different aliphaticmoieties containing 1 to 14 carbon atoms, and X^(⊖) stands for the acidanion of an organic or inorganic acid HX.
 2. The aqueous, cationicallystabilized primary dispersion according to claim 1, wherein the moietyR¹ in the aliphatic group Gr_(ali2) has a functional group selected fromthe group consisting of hydroxyl groups, thiol groups, primary aminogroups, and secondary amino groups in the beta-position with respect tothe nitrogen atom in the general formula of the emulsifier according toclaim
 1. 3. The aqueous, cationically stabilized primary dispersionaccording to claim 2, wherein: Gr_(ali1) is linear, unsubstituted, andfree of heteroatoms and has one to three carbon-carbon double bonds,Gr_(arom) is a phenylene or naphthylene group, and Gr_(ali2) is linear,contains a hydroxyl group in the beta-position with respect to thenitrogen atom in the general formula of the emulsifier (EQ), andadditionally contains O in the form of an ether group as a heteroatom.4. The aqueous, cationically stabilized primary dispersion according toclaim 1, wherein at least two of the moieties R¹, R², R³, and R⁴ bear afunctional group selected from the group consisting of hydroxyl groups,thiol groups, primary amino groups, secondary amino groups, and mixturesthereof.
 5. The aqueous, cationically stabilized primary dispersionaccording to claim 4, wherein in addition to bearing a functional groupselected from the groups consisting of hydroxyl groups, thiol groups,primary amino groups and secondary amino groups, the at least twomoieties R², R³, and R⁴ bear at least one additional functional groupselected from ether groups, ester groups, and amide groups.
 6. Theaqueous, cationically stabilized primary dispersion according to claim1, wherein a mixture of emulsifiers (EQ) is used in which more than 50mol-% of the moieties R′ in the emulsifiers (EQ) have carbon-carbonmultiple bonds.
 7. The aqueous, cationically stabilized primarydispersion according to claim 1, wherein the olefinically unsaturatedmonomer (A) is selected from the group consisting of: a1) (meth)acrylicacid esters which are free of acid groups; a2) monomers which bear atleast one hydroxyl group, one primary amino group, one secondary aminogroup, one tertiary amino group, one quaternary amino group, onealkoxymethylamino group or one imino group per molecule, which are freeof acid groups and which are different from the emulsifiers (EQ); a3)monomers which bear at least one acid group per molecule which may beconverted to the corresponding acid anion group; a4) vinyl esters ofmonocarboxylic acids, branched in the alpha-position, containing 5 to 18carbon atoms in the molecule; a5) reaction products of acrylic acidand/or methacrylic acid with the glycidyl ester of a monocarboxylic acidbranched in the alpha-position and containing 5 to 18 carbon atoms permolecule; a6) cyclic or acyclic olefins; a7) (meth)acrylic acid amides;a8) monomers containing epoxy groups; a9) vinyl aromatic hydrocarbons;a10) acrylonitrile or methacrylonitrile; a11) vinyl compounds selectedfrom the group of vinyl halides, vinylidene dihalides, N-vinyl amides,vinyl ethers, and vinyl esters that are different from the monomers a4);a12) allyl compounds; a13) polysiloxane macromonomers having a numberaverage molecular weight M_(n) of 1000 to 40,000 and an average of 0.5to 2.5 ethylenically unsaturated double bonds per molecule; a14)acryloxysilane-containing vinyl monomers; and mixtures thereof.
 8. Theaqueous, cationically stabilized primary dispersion according to claim7, wherein the olefinically unsaturated monomer (A) is selected from thegroup consisting of monomers a1), a2), a9) and mixtures thereof.
 9. Theaqueous, cationically stabilized primary dispersion according to claim7, wherein a mixture of olefinically unsaturated monomers (A) is usedwhich comprises: monomers a1) selected from the group of (meth)acrylicacid alkyl esters or (meth)acrylic acid cycloalkyl esters containing upto 20 carbon atoms in the alkyl or cycloalkyl moiety, monomers a2)selected from the group comprising monomers which bear at least onehydroxyl group, one primary amino group, one secondary amino group, onetertiary amino group or one quaternary amino group, and styrene asmonomers a9).
 10. A method for producing an aqueous cationicallystabilized primary dispersion according to claim 1 comprising the stepsof: introducing the olefinically unsaturated monomer(s) (A) and theemulsifier(s) (EQ) and optionally a crosslinking agent and/or furtherbinders into an aqueous medium, (1) converting the components of step(1) to a mini-emulsion by use of the action of shear forces, and (2)then carrying out an emulsion polymerization.
 11. The method accordingto claim 10, wherein in step (1) one or more crosslinking agents areselected from the group consisting of blocked polyisocyanates,tris(alkoxycarbonylamino)triazines, and completely etherified aminoplastresins.
 12. The method according to claim 10, wherein in step (1) anepoxy amine adduct is used as a further binder.
 13. The method accordingto claim 10, wherein the emulsion polymerization is carried out at atemperature of 25 to 95° C. and/or a pressure of 1.5 to 3000 bar. 14.The method according to claim 10, wherein the emulsion polymerization isinitiated by at least one water-soluble initiator selected from thegroup consisting of sodium persulfate, potassium persulfate, ammoniumpersulfate, tert-butyl hydroperoxide, and mixtures thereof.
 15. Acoating composition comprising an aqueous, cationically stabilizedprimary dispersion according to claim
 1. 16. The coating compositionaccording to claim 15, wherein it is an electrodeposition coatingcomposition.
 17. An electrodeposition coating composition comprising anaqueous, cationically stabilized primary dispersion according toclaim
 1. 18. The electrodeposition coating composition according toclaim 17, wherein the electrodeposition coating composition iscathodically depositable.
 19. An electrically conductive substrate thatis coated with a coating composition according to claim
 15. 20. Theelectrically conductive substrate according to claim 19, wherein it is ametallic substrate.
 21. The electrically conductive substrate accordingto claim 19, wherein said substrate is an automotive body or a partthereof.
 22. An emulsifier (EQ) having the following general formula:R¹—N⁻(R²)(R³)(R⁴)X^(⊖), wherein, R¹ is a moiety with 15 to 40 carbonatoms which contains at least one aromatic group and at least onealiphatic group, and which contains at least one functional groupselected from the group consisting of hydroxyl groups, thiol groups,primary amino groups, secondary amino groups, at least one carbon-carbonmultiple bond, and mixtures thereof, and wherein the R¹ moiety has thestructure Gr_(ali1)-Gr_(arom)-Gr_(ali2)-, where Gr_(arom) stands for anaromatic group, Gr_(ali1) stands for a first aliphatic group, andGr_(ali2) stand for a second aliphatic group, wherein the Gr_(ali1)group has at least one carbon-carbon multiple bond and the Gr_(ali2)group has the at least one functional group selected from hydroxylgroups, thiol groups, and primary or secondary amine groups; R², R³, andR⁴, independently of one another, are the same or different aliphaticmoieties containing 1 to 14 carbon atoms; and X^(⊖) stands for the acidanion of an organic or inorganic acid.